Freestanding Liquid Propane gas (LPG) heaters are used for heating patio surroundings. Though popular, they have quite a number of limitations. First, conventional LPG patio heaters do not operate with an optimal efficiency to adequately heat a sizable area. they have approximately 40% heat energy conversion rate. Second, in the presence of wind, the efficiency of LPG patio heater is further reduced. Third, LPG patio heaters need to be refilled and the frequency of which depends on the extent of usage. The cost to operate an LPG patio heater is approximately eight times greater than operating a Short-Wave-Infrared (SWI) heater. Fourth, conventional LPG patio heaters tend to be rather bulky and therefore difficult to relocate due to its requirement to house a large and heavy LPG tank. Fifth, limited by the requirement to house a large and heavy LPG tank, many aesthetically more appealing designs cannot be implemented. Sixth, due to the requirement to dissipate exhaust fumes, LPG heaters can only be safely operated in an outdoor environment. This substantially reduces the utility opportunities of LPG heaters.
Many existing SWI heater systems are wall mounted SWI heaters, or tripod mounted SWI heaters. Wall mounted SWI heaters can only be used where they are mounted. Thus, they can serve limited purposes. Many SWI heaters that are not wall-mounted are supported by simple tripod stands. Tripod stands are obtrusive and can be accidentally tripped thus create both a safety hazard and a fire hazard.
SWI heaters have a heat energy conversion rate of approximately 92% and can be used indoors or outdoors. SWI heaters can be directly aimed toward an object to be heated whereas LPG heaters are designed to heat the ambient environment surrounding the heaters and whatever objects within the ambient environment heating zone. However, this means the object to be heated must be in the path of the infrared light waves. Wall mounted and tripod mounted units are often not capable of being in a close enough proximity to the objects to be heated.
SWI heaters rely on electricity as its energy source. Most home circuits have a 15 ampere limitation and commercial offices may have a 20 ampere limitation. With 110-120 VAC power supplied in average households, SWI heaters cannot consume a power rating exceeding 1650-1800 watts. Given voltage fluctuations do occurred for various reasons, a theoretical limit of 1650 watt is possible but a more prudent limit of 1500 watts may be more appropriate to provide added safety precautions. Limiting the maximum wattage to less than 1500 watts limits the utility value of SWI heaters. However, allowing SWI heaters to function at the prudent maximum residential power rating of 1500 watts might raise some legitimate safety concerns. To address these concerns, the present invention provides a number of safety mechanisms to eliminate the safety concerns while allowing SWI heaters to function at the prudent maximum power ratings of 1500 watts for residential use.
Of course the present invention may be used in commercial settings and industrial settings. If so, the maximum power consumption may be raised far above that for residential use. The safety mechanisms addressed in the present invention would become even more important.